The present invention relates generally to nuclear fuel containment, and more particularly to a capsule and related method for storing or transporting individual nuclear fuel pins or rods including damaged rods.
Reactor pools store used fuel assemblies after removal and discharge from the reactor. The fuel assemblies and individual fuel rods therein may become damaged and compromised during the reactor operations, resulting in cladding defects, breaking, warping, or other damage. The resulting damaged fuel assemblies and rods are placed into the reactor pools upon removal and discharge from the reactor core. Eventually, the damaged fuel assemblies, rods, and/or fuel debris must be removed from the pools, thereby allowing decommissioning of the plants.
The storage and transport regulations in many countries do not allow storage or transport of damaged fuel assemblies without encapsulation in a secondary capsule that provides confinement. Due to the high dose rates of used fuel assemblies post discharge, encapsulating fuel assemblies is traditionally done underwater. Furthermore, some countries may require removal of individual damaged fuel rods from the fuel assembly and separate storage in such secondary capsules. Processes already exist for removing single rods from a used fuel assembly and encapsulation. Subsequent drying of damaged fuel after removal from the reactor pool using traditional vacuum drying is exceedingly challenging because water can penetrate through cladding defects and become trapped inside the cladding materials.
An improved fuel storage system and method for drying, storing, and transporting damaged fuel rods is desired.